Flat-article separating apparatus for an automatic mail handling system and the like

ABSTRACT

A flat-article separating apparatus for an automatic mail handling system uses a feeding device to feed flat articles along an article transport path and means installed on the transport path to exert a braking force on the flat articles being transported along the transport path. The braking force is gradually increased along the transport path to progressively separate the flat articles. When desired, a pair of accelerating pinch rollers at the end of the transport path complete the separation process.

United States Patent [191 Yoshimnra 11] 3,869,117 Mar. 4,1975

[ FLAT-ARTICLE SEPARATING APPARATUS FOR AN AUTOMATIC MAIL HANDLING SYSTEMAND THE LIKE [75] Inventor:

[73] Assignee: Nippon Electric Company, Limited,

Tokyo, Japan [22] Filed: Apr. 24,1973 [21] Appl. No.2 354,051

Shoichiro Yoshimura, Tokyo, Japan [30] Foreign Application Priority Data Apr. 27, 1972 Japan 4742483 [52] US. Cl 271/270, 198/35, 271/35, 271/182 [51] Int. Cl B6511 3/46 [58] Field of Search 271/46, 182, 183, 34, 35,

[5 6] References Cited UNITED STATES PATENTS Perssonm 271/149 X 3,219,339 11/1965 Gutierrez 271/34 OTHER PUBLICATIONS Straach, IBM Tech. Disclosure, Continuous Spring Rail," Vol. 13,No. 5, 10-1970.

Primary E.rmniner-James B. Marbert Assistant ExaminerBruce H. Stoner, Jr. Attorney, Agent, or FirmSughrue, Rothwell, Mion, Zinn & Macpeak 57 ABSTRACT A flat-article separating apparatus for an automatic mail handling system uses a feeding device to feed flat articles along an article transport path and means installed on the transport path to exert a braking force on the flat articles being transported along the trans port path. The braking force is gradually increased along the transport path to progressively separate the flat articles. When desired, a pair of accelerating pinch rollers at the end of the transport path complete the separation process.

6 Claims, 7 Drawing Figures FLAT-ARTICLE SEPARATING APPARATUS FOR AN AUTOMATIC MAIL HANDLING SYSTEM AND THE LIKE This invention relates to an automatic flat-article separating apparatus for use in an automatic mail-handling system and the like.

DESCRIPTION OF THE PRIOR ART An automatic feeding apparatus for flat articles such as cards, envelopes and postcards, is designed, as shown in the US. Pat. No. 3,219,339, to feed the flat articles one by one. In such an apparatus, a plurality of flat articles are often transported as they are .overlapped with each other. Such overlap-feeding causes errors in the automatic mail handling system. To guarantee an accurate mail handling, the overlapped flat articles mustbe separated from each other.

For this purpose, various kinds of flat-article separating apparatuses have been proposed. However, those conventional'apparatuses have a complicated mechanism and require a large space for installation and have a relatively low reliability.

SUMMARY or THE INVENTION BRIEF DESCRIPTION OF THE DRAWINGS The features and advantages of this invention will be understood from the following detailed description of the preferred embodiments taken in conjunction with the accompanying drawings, wherein:

FIG. 1 schematically shows a first embodiment of this invention;

FIGS. 2(A), 2(B), 2(C) and 3 illustrate various mode of opeation of the first embodiment; and

FIGS. 4 and 5 schematically show a second and a third embodiments of this invention, respectively.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1, the first embodiment of this invention comprises a stacker-feeder 1, an endless belt 6 having an outer surface lined with rubber, a forcingback roller 7 rotating counter to the belt 6, and accelerating pinch rollers 8 and 9 disposed at the end of the belt 6. A clearance 5 is given between the roller 7 and the belt 6 to allow the passage of the thickest possible flat articles to be processed. The belt 6 extends from the bottom of the stacker-feeder l to the pinch rollers 8 and 9, and is driven at a constant speed in the direction of an arrow 3 by rollers 10 and 11.

A friction braking means 12 is disposed above and in parallel with the belt 6. The friction braking means 12 is composed of a baseboard 13, a plurality of leaf springs 14 obliquely implanted in the lower surface of the baseboard 13, and frictional members 15 attached to the tip of the leaf springs 14 for exerting frictional and braking force upon the flatarticles on the belt 6. The leaf springs-l4 are set to exert, on the flat-articles through the individual frictional member 15, gradually increasing frictional and braking force toward the delivery end of the belt 6, with thefriction at thefrictional member 15 made smallest while that at the member 15', greatest. This leaf-spring setting may be modified arbitrarily. For instance, the pitches of the leaf springs 14 may be made shorter toward the delivery end. Alternatively, the baseboard 13 may be slightly tilted downward toward the delivery end to achieve the same effect.

The belt surface and the frictional member 15 should be made of materials satisfying the relationship:

where, K, is the coefficient of friction between the belt surface and the flat article, K the corresponding value between the frictional member and the flat article, and K the similar value between the flat articles. A satisfactory result has been obtained by using natural rubber for the surface of the belt 6 and a synthetic rubber for the frictional members 15.

The flat articles stacked in the stacker 1 are drawn out in succession through the clearance 5 in the direction of the arrow 3 by the friction with the outer surface of the belt 6. Assuming that several flat articles in an overlapped state have passed through the clearance 5, the flat articles are spread and rearranged successively as schematically shown in FIGS. 2(A), (B) and (C), in which the braking plane defined by the array of the frictional members 15 is approximated by the line 12'.

FIG. 2(A) shows the initial state of overlapped flat articles passed through the clearance 5. Under this condition, the lowermost flat article 2a tends to be carried leftward by the action of the belt 6, whereas the uppermost flat article 2e undergoes a braking by the braking plane 12'. Accordingly, the overlapped flat articles are gradually separated from each other, beginning with the state depicted by FIG. 2(A) then changing to the states shown in FIGS. 2(8) and 2(C), respectively.

The lowermost flat article 2a comes into contact over its entire lower surface with the belt surface which provides the greatest coefficient of friction. Therefore, no matter whether or not its upper surface comes into direct contact with the braking plane 12', the driving force exerted by the belt surface overcomes the braking force. Accordingly, the lowermost flat article is transported leftward at the same speed as the belt 6 without slipping on the belt surface. On the other hand,

the uppermost flat article 2e in frictional engagement with the braking plane 12' over its entire upper surface, undergoes maximum braking force, while the lower surface intercepted by the underlying flat article 2d is brought in only a partial frictional engagement with the surface of the belt 6. Thus the braking force always overcomes the driving force and the flat article 2e tends to come to a stop. A slip caused between the flat articles 2a and 2e tends to be distributed or divided among the intermediate flat articles 2b, 2c and 2d. and the overlapped flat-articles are separated or spread out to the state depicted by FIG. 2(C), in which a small overlapping is left between any two adjacent flat articles.

To simplify the description, it is assumed referring to FIG. 3 that the flat articles 2f, 2g, 2h and 2i are equal same in width and length, and their relative dispositions vary markedly. The lower surface of any flat article comes into direct contact either with the underlying flat articleor with the belt surface. Because the coefficient of friction given by the belt surface is much greater than that between the flat articles themselves, any flat article having a greater contact area with the belt surface will receive a greater driving force therefrom. Therefore, the flat article 2h receives a greater driving force than the flat article 2g, because l l,. Each fiat-article is in frictional engagement with either the overlying flat article or the braking plane 12', but the coefficient of friction offered by the latter is much greater, with the result that any flat article having a greater contact area with the latter receives a greater braking force. Thus the flat article 2g receives a greater braking force than the flat article 2h, because l l as shown in FIG. 3. Thus, a decelerating force acts more intensely on the flat article 2g, whereas an accelerating force acts more intensely on the flat article 2h. Accordingly, both 1 and 1 increase while 1 decreases to correct the variation in relative portions of these flat articles.

In this embodiment, the leaf springs 14 having with the frictional members 15 are designed to have gradually increasing frictional forceat a constant gradient along the braking plane.

Since the leading edge portion of each flat article is usually intercepted by the underlying flat article thereby preventing it from getting into contact with the belt surface, its contact area with the belt surface is inevitably biased to its rear half portion, whereas the contact area with the braking plane is biased to the front half portion. The area in contact with the braking plane receives a greater pressure than that in contact with the belt surface. The pressure difference is increase with the amount or the number of the overlapped flat articles.

The pressure difference causes the braking force acting on the upper surface of the flat article to overcome the driving force acting on the lower surface in spite of the fact that the coefficient of friction given by the belt surface has been chosen to be greater than that offered by the braking plane, with the result that the overlapped flat articles are spread out in succession. As the number of the overlapped articles decreases with the spreading action, the pressure difference is reduced and the driving force from the belt surface is overwhelmingly increased. Thenceforth, each flat article is placed solely under the control of the belt and is transported, without undergoing any spread nor slip, at the same speed as the belt.

Thus, the overlapped flat articles are gradually spread out into a controlled stream in which individual flat articles are overlapped in succession by a small,

constant am ount depending on the pressure gradient of The accelating rollers are indispensable to an automatic mail-culling, cancelling or sorting machine. But,

'such rollers canbe dispensed with where the object of feeding is merely conveyance or stacking. Therefore,- the accelerating rollers are not essential to this invention.

It will be obvious to those skilled in the art that a number of modifications of the friction braking means are possible besides the one described and illustrated in FIG. 1. For instance, coil springs or other resilient members fastened to the back of the base board can be substituted for the leaf springs in order to obtained the frictional pressure for braking.

The equivalent effect can be obtained by other equivalent means. FIG. 4 shows schematically another embodiment for producing the required pressures to act on the flat articles through leaf springs 14 acting on a thin sheet 16 of the same material as that used for the belt.

FIG. 5 shows still another embodiment for installing a number of rubber rollers 17 in parallel relationships with respect to the belt 6 and rotating each roller counter to the run of the belt or at an extremely low speed in the same direction.

As a further possible embodiment, it is possible to install the pressure means on the inner surface of the belt and fix the braking means. An array of rubber rollers can be adopted as another kind of the conveyor means.

It will be apparent that the pressure application points by the frictional member 15 should be so finely distributed as to enable a plurality of points act simultaneously on each single fiat article. Thus, it may be appreciated that the embodiments shown are only exemplary and that various modifications can be made in construction and arrangement within the scope of the invention as defined in the appended claims.

What is claimed is:

1. A flat-article separating apparatus for an automatic mail handling system and the like, comprising:

an article transport path including a moving surface,

means for feeding flat articles along said article transport path, and

braking means installed on said article transport path for giving a braking force to said flat articles under transportation along said article transport path, said braking force being gradually increased toward the delivery and of said article transport path, said braking means including a braking surface juxtaposed to said moving surface whereby the uppermost of a stack of overlapping flat articles comes into substantial contact with the surface of said braking means and the lowermost of said stack comes into substantial contact with said moving surface thereby causing said stack to be progressively spread along the direction of movement of said moving surface, said moving surface and the surface of said braking means being made of materials which satisfy the relationship where K is the coefficient of friction between said moving surface and a flatarticle to be separated, K is the coefficient of friction between said braking surface and a flat article to be separated, and K 'is the coefficientof friction between flat articles to be separated.

2. A flat-article separating apparatus as recited in claim 1 wherein said moving surface is natural rubber and said braking surface is synthetic rubber.

3. A flat-article separating apparatus as recited in claim 1 wherein said moving surface is a conveyor belt and said braking surface comprises a plurality of frictional members and resilient means connected to said frictional members for exerting increasing pressure beclaimvl wherein said moving surface is a conveyor belt and said braking surface comprises a plurality of rollers.

6. A flat-article separating apparatus as recited in claim 5 wherein said plurality of rollers each rotate providing a tangential surface velocity less than the velocity of the surface of said conveyor belt. 

1. A flat-article separating apparatus for an automatic mail handling system and the like, comprising: an article transport path including a moving surface, means for feeding flat articles along said article transport path, and braking means installed on said article transport path for giving a braking force to said flat articles under transportation along said article transport path, said braking force being gradually increased toward the delivery and of said article transport path, said braking means including a braking surface juxtaposed to said moving surface whereby the uppermost of a stack of overlapping flat articles comes into substantial contact with the surface of said braking means and the lowermost of said stack comes into substantial contact with said moving surface thereby causing said stack to be progressively spread along the direction of movement of said moving surface, said moving surface and the surface of said braking means being made of materials which satisfy the relationship K1 > K2 >> K3 where K1 is the coefficient of friction between said moving surface and a flat article to be separated, K2 is the coefficient of friction between said braking surface and a flat article to be separated, and K3 is the coefficient of friction between flat articles to be separated.
 2. A flat-article separating apparatus as recited in claim 1 wherein said moving surface is natural rubber and said braking surface is synthetic rubber.
 3. A flat-article separating apparatus as recited in claim 1 wherein said moving surface is a conveyor belt and said braking surface comprises a plurality of frictional members and resilient means connected to said frictional members for exerting increasing pressure between said frictional members and said conveyor belt along the direction of movement of the belt.
 4. A flat-article separating apparatus as recited in claim 3 wherein said resilient means comprises a plurality of leaf springs obliquely inclined to said conveyor belt and connected to respective ones of said frictional members.
 5. A flat-article separating apparatus as recited in claim 1 wherein said moving surface is a conveyor belt and said braking surface comprises a plurality of rollers.
 6. A flat-article separating apparatus as recited in claim 5 wherein said plurality of rollers each rotate providing a tangential surface velocity less than the velocity of the surface of said conveyor belt. 